diff --git a/docs/refguide.xml b/docs/refguide.xml
index 7071de373..a37ddb462 100644
--- a/docs/refguide.xml
+++ b/docs/refguide.xml
@@ -3071,12 +3071,14 @@ seconds, respectively, between probes.  <option>T3</option><indexterm><primary><
 default behavior, which includes parallelization.
 <option>-T4</option>
 does the equivalent of <option>--max-rtt-timeout 1250ms --min-rtt-timeout 100ms
---initial-rtt-timeout 500ms --max-retries 6</option> and sets the maximum TCP scan delay
-to 10 milliseconds.  <option>T5</option>
+--initial-rtt-timeout 500ms --max-retries 6</option> and sets the maximum TCP and SCTP scan delay
+to 10ms.  <option>T5</option>
 does the equivalent of
 <option>--max-rtt-timeout 300ms --min-rtt-timeout 50ms
---initial-rtt-timeout 250ms --max-retries 2 --host-timeout 15m --script-timeout 10m</option> as well as
-setting the maximum TCP scan delay to 5&nbsp;ms.</para>
+--initial-rtt-timeout 250ms --max-retries 2 --host-timeout 15m --script-timeout 10m --max-scan-delay</option> as well as
+setting the maximum TCP and SCTP scan delay to 5ms.
+Maximum UDP scan delay is not set by <option>T4</option> or <option>T5</option>, but it can be set with the <option>--max-scan-delay</option> option.
+</para>
 
         </listitem>
       </varlistentry>
diff --git a/nmap.cc b/nmap.cc
index f0354cf95..1eb0b3aea 100644
--- a/nmap.cc
+++ b/nmap.cc
@@ -1335,6 +1335,7 @@ void parse_options(int argc, char **argv) {
         o.setInitialRttTimeout(500);
         o.setMaxTCPScanDelay(10);
         o.setMaxSCTPScanDelay(10);
+        // No call to setMaxUDPScanDelay because of rate-limiting and unreliability
         o.setMaxRetransmissions(6);
       } else if (*optarg == '5' || (strcasecmp(optarg, "Insane") == 0)) {
         o.timing_level = 5;
@@ -1344,6 +1345,7 @@ void parse_options(int argc, char **argv) {
         o.host_timeout = 900000;
         o.setMaxTCPScanDelay(5);
         o.setMaxSCTPScanDelay(5);
+        // No call to setMaxUDPScanDelay because of rate-limiting and unreliability
         o.setMaxRetransmissions(2);
 #ifndef NOLUA
         o.scripttimeout = 600; // 10 minutes